Antinutrients are natural or synthetic compounds that interfere with the absorption of nutrients. Here is an outline of the top four:
Phytates bind to minerals in your gut preventing them from being absorbed by your body. They also suppress the absorption of iron, zinc, calcium and phosphorus. studies have also suggested that diets heavy in phytates are responsible for the widespread zinc deficiencies seen commonly in the developing world.
Phytates are most commonly found in beans, grains, seeds and legumes. Beans are the biggest concern, but good news if you’re a bean lover- soaking, sprouting and fermenting all reduce phytate levels.
Lectins are anti-nutrients that disrupt the functioning of the epithelium (the thin layer of cells lining your gut that keeps undigested food from slipping into your bloodstream). Over time, lectins in the diet will actually create holes in the epithelium, referred to as "leaky gut syndrome".
When the epithelium is compromised, incompletely-digested particles from your food can slip into your bloodstream. Your body treats these food particles as a threat and triggers an immune response that creates systemic inflammation and food sensitivities. This is a similar mechanism to how wheat gluten creates holes in the epithelium. Lectins have also been shown to disrupt gut bacteria function.
Lechtins can be found in beans and grain. Soy beans and kidney beans are the biggest concerns, however, cooking and fermenting reduce lectins quite a bit.
Saponins have a soap-like foaming property when they're added to liquid. They disrupt epithelial function and create other digestive issues. Saponins have also been connected to damaging red blood cells, inhibiting enzymes and interfering with thyroid function.
They are found in soy beans, chick peas, oats and quinoa. We've recently learned that quinoa has particularly high levels of saponins, making it a real concern.
Cooking doesn't have much of an impact, nor does sprouting or fermentation. Saponins can be removed via alcohol extraction, but this obviously isn't practical.
Oxalates interfere with calcium absorption in the body. They will also crystalize in tissues if consumed regularly, creating arthritis-like symptoms and even kidney stones. Foods with the highest oxalate levels are kale, spinach, chard and other hearty leafy greens.
Cooking will slightly reduce levels of oxalates. You can also take a calcium/magnesium supplement when eating these foods - calcium and magnesium bind to the oxalates in your stomach and prevent them from being absorbed.
HOW BAD ARE THESE ANTI-TOXINS?
What all of these plant toxins have in common is that they only have significant negative impacts if they are allowed to accumulate in the body.
Eating beans or kale once a week realistically won't have a negative impact. Our bodies are pretty good at clearing out toxins, including plant toxins, when given enough time – just make sure you aren’t eating them at every meal/several days in a row. Awareness is key – if your health (or general feeling of well-being) declines, you can start looking back at the foods you’ve been consuming as a possible culprit.
WHICH FOODS ARE THE MOST PROBLEMATIC?
Soy appears all over the list above. If the phytoestrogen and mold-toxin issues weren't enough, the high levels of plant-toxins in soy should be enough to convince you to remove it from your diet.
Quinoa - a particularly potent source of saponins, so consuming it with any regularity puts you at risk for gastrointestinal issues.
Grains, beans and legumes - with grains, plant toxins are perhaps the least of your worries, as mold contamination is realistically a much bigger issue.